Aircraft with rotary wings

ABSTRACT

Aircraft with rotary wings, characterized in that it comprises a nacelle (1) surrounding the user who seats on a seat (9) slidingly arranged in the medial plane of said nacelle, substantially in the normal displacement direction of flight of the aircraft, two parallel crowns (40-41) carried by the nacelle and imparted with identical rotational motions but in inverted directions about a common axis, extending substantially at the center of the nacelle, perpendicularly to the plane of said crowns, each of the crowns supporting at least one pair of blades (48-49, 50-51) or wings diametrically opposite and arranged in the prolongation of each other, drive means (19-37) for driving the crowns about the nacelle and means (66-67) for changing in each pair of blades the pitch thereof in an equal but opposite way for each of them.

The present invention relates to a rotary-wing aircraft having aparticularly simple structure and very light weight which makes itpossible in particular although not exclusively to use the aircraft as aULM (Ultra-Light Motorized) machine.

There already exist known designs of airplanes of the vertical-takeoffand landing type, in particular of the rotary wing or airfoil typecommonly designated as helicopters or autogiros. In their design conceptand general principles of operation, however, these airplanes aresubject to drawbacks arising in particular from the use of a rotor fordriving the lifting blades in which the mechanism for driving and pitchcontrol or in other words for varying the angle of incidence of theblades is heavy and costly, and requires difficult maintenance.Furthermore, the rotor blades usually serve to lift a cabin or cockpitwhich is occupied by the pilot and/or the passengers of the aircraft andwhich accordingly constitutes an obstacle to the flow of air swept bysaid blades. Finally, the flight efficiency of such aircraft is of a loworder, thus resulting in high fuel consumption. In addition, thepurchase price and maintenance cost of these machines are usuallyprohibitive for individual use.

The present invention has for its object a rotary-wing aircraft whichovercomes these disadvantages while also permitting operation by a userwho has only a limited knowledge of flying and navigation, the airplanebeing capable of taking-off and landing without requiring any made-upplatform or any other similar structures, the sole requirement being afree space which is sufficient to permit free rotation of the blades ofthe airplane. In addition, this latter has low fuel consumption,requires only limited maintenance and can be constructed for a very lowpurchase price. Furthermore, the aircraft in accordance with theinvention does not call for costly structural materials but makes itpossible on the contrary to use standard commercially availablematerials such as wood, light alloys, plastics. Finally, the aircraftlends itself to many alternative embodiments having the same conceptualbasis which is common to each embodiment.

To this end, the aircraft considered is characterized in that itcomprises a nacelle surrounding the user who is seated on a seat mountedin the median plane of said nacelle for sliding motion substantially inthe normal direction of displacement of the aircraft in flight, twoparallel rings carried by the nacelle and driven in identical movementsof rotation but in opposite directions about a common axis extendingsubstantially at the center of the nacelle at right angles to the planeof said rings, the function of each ring being to support at least onepair of wing-blades or airfoils which are diametrically opposite andlocated in the line of extension of each other, means for driving therings about the nacelle and means whereby the blade pitch in each pairof blades can be varied in an equal but opposite manner in each case.

Thus, with the aircraft in accordance with the invention, the heads ofthe blade-driving rotors which represent a particularly high cost inknown aircraft and also have a certain fragility are henceforth replacedby two counterrotating rings for driving these blades in rotation whilemaintaining a predetermined position-setting and incidence of theselatter.

Moreover, the aircraft in accordance with the invention is so arrangedthat the center of gravity of this latter, which is located between thetwo rings, can permit easy control of the aircraft by the user. It ispossible in particular to modify the trim of the aircraft at will,simply by displacement of the user himself on his seat which is slidablymounted with respect to the nacelle, thereby producing during flight athrust on the unit which ensures propulsion of the aircraft as a resultof forward inclination of the blades of the rotary wings or, on thecontrary, in the case of rearward displacement of the seat, an oppositemodification of trim and a braking effect on the aircraft as a result ofreverse inclination of the blades.

Advantageously, the nacelle is provided with means for supporting theaircraft on the ground, thus ensuring stability of this aircraft when atrest. Preferably, these means are constituted by a rigid supportstructure forming an extension of the nacelle and provided with skids,small wheels or the like.

In accordance with a particular feature of the invention, the means fordriving the rings include at least one driving wheel which is driven inrotation about a shaft parallel to the plane of the rings, said shaftbeing supported by the nacelle and located at equal distance from bothrings, the periphery of the wheel being applied against the oppositeface of each ring in such a manner as to ensure that the rotation ofsaid wheel actuates both parallel rings at the same speed but inopposite directions.

Advantageously, the driving wheel is provided with a rolling-drive tireformed of rubber and having the function of driving the rings byfrictional contact with these latter. The driving-wheel shaft passesfreely through a carrier block rigidly fixed to the nacelle and iscoupled by means of a free-wheel mechanism to a flywheel over which ispassed a driving-belt actuated by a pulley which is in turn driventhrough a centrifugal clutch by the output shaft of an internalcombustion engine.

In accordance with another particular feature, the connection betweenthe internal combustion engine and the centrifugal clutch is establishedby means of a resilient coupling device which is capable of permittingslight misalignments between the output shaft of said engine and theclutch. Preferably, the internal combustion engine is carried by thenacelle by means of fastening collars or the like and locking nuts whichmake it possible to adjust its relative position on the nacelle at thetime of assembly.

In the foregoing arrangement, the driving wheel is in direct frictionalcontact with the rings. However, and in accordance with anotheralternative embodiment, the driving wheel can be constituted by atoothed wheel engaged in the same manner as a gear-wheel with a flexibleslotted track provided on each opposite face of the two rings which aredriven by said wheel.

Advantageously, each ring is carried by the nacelle by means of aplurality of sets of runner-wheels located in circumferentially spacedrelation around said ring, each set being optionally constituted bythree runner-wheels rotatably mounted on axle-pins attached to thenacelle and applied on the one hand in the case of two runner-wheelsagainst both faces of the ring and on the other hand in the case of thethird runner-wheel against the internal edge of this latter which isopposite to the blades.

In order to permit a permanent or predetermined variation in pitch ofthe blades of the wings or airfoils associated with the rotary wings,each of these rings is provided opposite to each blade with an axialstud which supports this latter, which is fitted with a needlethrust-bearing and on which is engaged a sleeve designed for pivotaldisplacement about the stud, said sleeve being provided with anextension in the form of a stirrup-piece, the end of the blade beingmounted and fixed between the two arms of said stirrup-piece so as topermit a variation in pitch of the blade with respect to the ring byrelative rotation of the sleeve.

Preferably, each blade of the airfoil has two transverse extensionslocated in alignment with each other, the blades of one and the samepair being joined together around the nacelle by means of two crossedand tensioned cables fixed at the end of said extensions respectively atthe opposite extremities thereof so that a tractive force exerted in onedirection on one of the cables results in an opposite tractive force onthe other cable and conversely, the two blades of the same pair beingthus capable of pivoting about their axial supporting studs with anequal and opposite amplitude of rotation. Preferably also, the tensionapplied to the cables for ensuring relative pivotal displacement of theblades is adjusted by means of an assembly of distance-bars or similartensioning devices associated with the support extensions. Furthermoreand in accordance with a subsidiary characteristic feature of theinvention, the position of the two crossed cables for determining thepitch of the blades is controlled by means of electromagnetic deviceshaving two positions or by means either of a reduction-gear motor or ofa stepping motor for ensuring relative displacement of these cables inopposite directions.

As already indicated, displacement of the aircraft can be achieved in afirst simplified alternative form of construction by varying the trim ofthe machine, especially by displacement of its center of gravity as aresult of sliding motion of the seat on which the user is seated. Inanother alternative form of construction, the nacelle carries at the endopposite to the ring-displacement driving wheel an auxiliary wheel whichis freely driven by the movement of said rings, the axis of theauxiliary wheel being preferably located in the median plane of thenacelle opposite to that of the driving wheel, the auxiliary wheel beingprovided with a set of orientable radial vanes adapted to generate aforward aircraft-flight component in the direction of said median plane.

In the alternative embodiment given above, the auxiliary wheel ispreferably mounted at the end opposite to the ring-displacement drivingwheel, thus making it possible in particular and in combination with theother guiding and control means to ensure flight control of the aircraftwhile avoiding drift in particular and maintaining the rotary-wingblades at a strict setting of 180° when these rotary wings are eachprovided with one opposite pair of blades.

In order to permit sliding motion of the user's seat with respect to thenacelle in the first alternative embodiment mentioned in the foregoing,said seat is slidably mounted on at least one supporting bar locatedsubstantially in the vicinity of the lower ring and extending parallelto the median plane, the position of the seat being adjusted by the userby means of the reaction of an effort exerted by him on toe-clips orsimilar foot-rests arranged on the nacelle on each side of said planeand if necessary on a handlebar.

If so required, the sliding seat can be provided with a balancingcounterweight in order to compensate for the inadequate weight of auser, especially when the user's weight is less than sixty kilograms,for example.

According to other subsidiary characteristic features of the aircraft inaccordance with the invention, which can be utilized to advantageirrespective of the alternative embodiment adopted for directing theaircraft in flight, the nacelle supports at least one and preferably twofuel tanks placed between the rings on each side of the median plane ofthe nacelle. By way of alternative, the sliding seat can be providedwith a seat-back in which a main fuel tank or complementary fuel tank isplaced within the thickness of the seat-back.

Similarly and in accordance with another advantageous arrangement of theinvention, the nacelle supports lateral fins or ailerons on each side ofthe median plane so as to facilitate lateral movements of the aircraft.In addition, the nacelle is provided in the immediate vicinity of theuser's hands with devices for controlling the engine, ailerons andcables for adjusting the pitch of the blades as well as means fordirecting the movements of the aircraft in flight.

Thus and in accordance with another characteristic feature, each of thetwo rings carried by the nacelle is provided with at least one brakeadapted to be actuated by the user by means of a compensation bar forslowing-down the rotational motion of said ring and generating arelative-displacement torque between the two rings and inducing areaction on the aircraft, in particular in order to produce adisplacement of this latter during banking or while hovering.

Finally, in the transmission of motion from the engine to thering-driving wheel, means are advantageously provided for detectingengine failure in such a manner as to initiate automatic declutching ofthe engine and immediate autorotation of the wing blades carried by therings for free lifting of the aircraft until it finally lands under theaction of the downward velocity component as a result of its weight inthe autorotation regime.

By virtue of the practical application of the arrangements set forth inthe foregoing, the rotary-wing aircraft in accordance with the inventionpermits very simple control of its movements in all directions, eitherin hovering flight or in normal flight without a banking flight path orwith banking or yawing, this latter being obtained either by action ofthe brakes which produce lateral action on the upper ring or by thelateral ailerons, or by the combined effect of these two elements. Inall cases, initial control of the value of collective pitch of theblades and then subsequently, during flight, dynamic control of cyclicvariation in pitch of said blades carried by the rings as performed bythe crossed cables associated with each pair of blades of the airfoilmakes it possible to ensure perfect stability of the aircraft.Furthermore, since the blades of each wing are fixed on a rotary sleeve,it is thus possible to ensure automatic lift over the entire surface ofthis blade, the airflow swept by the wings being in addition undisturbedby the obstacle constituted by the aircraft nacelle by virtue of thefact that the rings are mounted around and externally of this latter.This results in very appreciably enhanced sustentation efficiency inrespect of a given airfoil surface area.

Other advantages and features of a rotary-wing aircraft designed inaccordance with the invention will become further apparent from thefollowing description of various examples of construction given by wayof indication and not by way of limitation with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic transverse sectional view of the rotary-wingaircraft in accordance with the invention, taken along a median plane ofdisplacement of the aircraft on a rectilinear flight path.

FIG. 2 is a front view of the aircraft of FIG. 1.

FIG. 3 is a top view of the aircraft in accordance with FIGS. 1 and 2.

FIG. 4 is a detail sectional view to a larger scale illustrating themeans employed for supporting the blades of the rotary wings whilemaking it possible in particular to adjust the pitch of the airfoil thusconstituted.

FIG. 5 illustrates in an alternative embodiment the structure of anauxiliary wheel for producing a displacement component on the aircraftin flight, especially in the median plane of the aircraft.

FIG. 6 is a sectional view of another constructional detail which makesit possible to generate a phase-displacement torque between the twodrive rings of the rotary wings.

As can be seen in particular in FIGS. 1 to 3, the aircraft underconsideration primarily includes a nacelle 1 of generally cylindricalshape and advantageously constituted by curved tubular members such asthe member 2 which are placed horizontally and joined to each other bymeans of a lateral wall 3. The tubes 2 and the wall 3 are formed of anysuitable lightweight material which may be of metal, for example, orwhich may have portions of plastic materials and even of wood. At thelower portion of the nacelle 1 are placed on each side of the medianplane of this latter which corresponds to the section plane of FIG. 1two longitudinal members 4 (FIG. 3) constituting a sliding-motionsupport for a seat 9 on which the user or pilot of the aircraft isseated. The longitudinal members 4 are rigidly fixed to the nacelleproper so as to constitute with this latter a rigid assembly havingextensions in the form of four ground support struts 5 which terminatein skids or the like. If so required, the skids 6 could be replaced bysmall wheels or by any other supporting means of a conventional designfor this type of aircraft. Stiffening members 7 enable the struts 5 ofthe nacelle to withstand the forces generated by the weight of theaircraft when it is resting on the ground. Similarly, the crossed cables8 can be stretched between these struts in order to ensure perfectrigidity of the assembly.

The seat 9 which is mounted within the nacelle in the lower portion ofthis latter is provided with a seating plate 10 beneath which extendguide brackets 11 carrying guide wheels 12 in order to permit easydisplacement of the seat in sliding motion on the longitudinal members 4while modifying under these conditions the position of the center ofgravity of the aircraft once the pilot is seated on said seat. Thislatter has a lower portion 13 on which the user installs himself, thisportion 13 being extended by a seat-back 14. Advantageously, the seat 9has a bucket-shaped profile and is provided with the usually safetymeans (rapidrelease seat-belt, strap or fastener) enabling the pilot tobe comfortably seated while being united with this seat, especially inorder to enable him to exert an effort by means of his feet on supports4a rigidly fixed to the nacelle 1 or else on a handlebar (not shown) andto displace the seat at will along its longitudinal members 4, thusadjusting the corresponding position of this latter in the median planeof the aircraft and displacing the center of gravity of the machine. Abalance-weight 15 can also be provided behind the seat 9 in order tocomplete the equipment of this latter, especially when the pilot is ofsmall build, so that his displacement with the seat does not producesufficient variation of the center of gravity to cause variation orcorrection of trim of the aircraft as will be explained hereinafter. Itwill be readily apparent that such a balance-weight must be avoided asfar as possible if the weight of the user is suitable since the aircraftin accordance with the invention has to be so designed as to achieveminimum weight by eliminating any unnecessary accessory having a netweight which penalizes the entire structure.

The nacelle 1 is advantageously provided on each side of the seat 9 withtwo fuel tanks 16 each having at its lower end an opening cock 17 and asupply line 18 connected to an internal combustion engine 19 which iscarried by the nacelle and delivers the power required for lifting andpropulsion of the aircraft. By way of alternative, the fuel reserve tankcould be placed within the thickness of the nacelle itself or evenbeneath the seat or within the seat-back, in which case means foradequate protection of the pilot would naturally be arranged around thefuel tank.

The engine 19 is fixed beneath the nacelle 1 by means of a tie-bar 20which supports said engine by means of clamps or collars (not shown) andlocking bolts 21. Preferably, the engine 19 is a two-stroke gasolineengine provided in the conventional manner with a lateral exhaust pipe22 and a muffler 23, the outlet of which is directed towards the rear ofthe aircraft. The engine 19 drives an output shaft 24 which is connectedby means of a resilient coupling device 25 of the "silent block" type orthe like to a first transmission shaft 26. The device 25 makes itpossible in particular to allow any slight misalignments of the shafts24 and 26 during operation. The transmission shaft 26 is rotatablymounted on bearings (not shown) mounted within a carrier block 27 whichis mounted at the front end of the nacelle and said shaft is providedwith a motion-transmission pulley 28 for driving a second intermediatepulley 30 by means of a belt 29. The shaft 26 also drives a centrifugalclutch 29a which is shown diagrammatically in the drawings and theconstructional detail of which has in itself little bearing on theinvention.

The movement of rotation of the intermediate pulley 30 as imparted tothe shaft 24 of the engine 19 in the manner which has been explainedabove is transmitted by a shaft 31 carried by the block 27 to a thirdpulley 32 which in turn transmits motion by means of a secondcountershaft drive belt 33 to an inertia wheel 34. This latter iscoupled to a final transmission shaft 36 by means of a free-wheelmechanism 35, the function of which will be explained in greater detailhereinafter. It is clearly apparent that the form of practicalconstruction of the mechanism for driving the shaft 36 from the engine19 could be made to include many alternative forms according to therelative position of these elements, the torque to be transmitted andthe space available. There is finally mounted at the end of the shaft 36a driving wheel 37 which, in its most simple version, is provided with acentral rim 38 and with a tire 39 at its periphery. In accordance withan essential feature of the invention, this tire is in frictionalcontact with two identical parallel rings 40 and 41 respectively whichare placed concentrically with the axis of the nacelle 1 in superposedhorizontal planes when the nacelle is resting on the ground, these ringswhich are consequently located at equal distances from the transmissionshaft 36 being thus driven in opposite directions with respect to eachother and at the same speed since these rings have the same diameter.Each ring 40 or 41 is supported opposite to the nacelle 1 by means ofbearing units 42 each consisting in the example considered of threerunnerwheels mounted to rotate freely on their respective axlepins, twoof these wheels 43 and 44 being applied against the top and bottom facesof the ring considered whilst the third wheel 45 runs on the inner edgeof the same ring. These bearing units 42 are provided in spaced relationabout the vertical axis of the nacelle at the level of each ring 40 and41 and in suitable number which can vary from three to eight as the casemay be. A device 46 for recording the speed of the rings is alsoprovided and preferably placed at the front end of the nacelle in themedian plane of the aircraft under the eyes of the pilot who is seatedon the seat 9. By way of example, this device 46 is constituted by atachometer roller which thus records the instantaneous speed of rotationof the ring 40 and transmits its measurement to a reading dial 47 fixedon the top tube 2.

Each ring 40 and 41 supports at least one pair of blades constituting inpairs a rotary wing or airfoil of the aircraft, the two blades (or evenfour blades if necessary) associated with the upper ring 40 beingdesignated in the drawings by the references 48 and 49, the two bladesof the lower ring 41 being designated by the references 50 and 51.

The connection between each blade and the corresponding ring isestablished in accordance with the invention by means of a specialfastening device 52 in rigidly fixed relation to the edge of the ringopposite to the edge against which the runner-wheels 45 are applied.This device comprises in particular a part 53 which is stationarilyfixed on the ring by means of fixing screws 53a and has an extension inthe form of a radial stud 54 as can be seen more precisely in the detailview of FIG. 4. On this stud is engaged an intermediate sleeve 55 whichis capable of rotating about the stud 54 by virtue of the assemblybetween this latter and the sleeve of a roller-bearing 56 The sleeve 55also has an internal flange 57 on which is applied a needlethrust-bearing 58, the complete assembly being fixed in position axiallyby means of a locking-nut 59. By virtue of the roller-bearing 56 and thethrustbearing 58, the sleeve 55 is therefore capable of free rotationabout the stud 54 in one direction or in the other and this arrangementmakes it possible to carry out variation of the blade pitch or in otherwords the relative inclination of the blades with respect to the planeof the corresponding ring 40 or 41. Each of the blades 48 to 51 isitself stationarily fixed on the end of the sleeve 55 which receivessaid blade and is accordingly designed in the form of a stirrup-piece61, final locking of the blades being carried out by means of a nut 62.

In order to adjust the amplitude of angular displacement of the bladeswith respect to the rings with a view to varying their relativeinclination in the manner mentioned in the foregoing and especially witha view to producing a variation of the so-called "collective pitch" ofthe airfoil while also permitting automatic and cyclic variation of thispitch during flight for the purpose of taking into account the effectsof turbulences set up by their rotation and the movements of theaircraft, another important feature of the invention consists inproviding on the external surface of each blade-supporting sleeve 55 twoextensions in the form of ears 63 and 64 located in the diametral lineof extension of each other so as to form together at the end of eachblade a kind of control arm for varying the orientation of the bladeabout the stud 54 which supports this latter in the plane of the ring.To this end, the ears 63 and 64 are provided with attachment holes 65for cable ends 66 and 67 respectively which are guided within sheaths 68in a groove 69 formed in the edge of the corresponding ring in such amanner as to ensure that the cable 66, for example, which is fixed onthe ear 63 of the sleeve 55 having the function of supporting the blade48 is attached to the ear 64 of the sleeve of the blade 49 which islocated opposite to the first, and conversely in the case of the cable67. The cables 66 and 67 are suitably stretched by means ofdistance-bars or other similar means (not shown) so that a tractiveforce exerted on one of these cables in one direction automaticallyproduces a tractive force on the other but in the opposite direction,thus causing pivotal displacement of the corresponding pair of blades48, 49 or 50, 51 with the same amplitude but in opposite directions.

The equipment of the nacelle is completed by means of variousaccessories having the function, as will be explained in detailhereinafter, of generating a forward aircraft-flight component incombination with the lifting action of the rotary wings. In particular,it has already been stated that the variation in trim of the assemblyfor inclining the blades in a variation such that the lift effect isaccompanied by a thrust effect, especially in the direction of themedian plane of the nacelle, can be achieved by producing a variation inposition of the sliding seat 9 by means of a forwardmotion or withdrawaleffect produced by the pilot himself.

In order to permit changes in direction of the aircraft during flighteither to the left or to the right, an advantageous possibility consistsin placing two ailerons or fins 70 fixed in particular on the rear sideof its support struts 5 and each pivotally mounted on a hinge-pin 71carried by one of said struts, control of orientation of said aileronsbeing carried out by means of a control stick 72 which is actuated bythe pilot. A coupling-bar 73 is preferably pivotally attached to bothailerons 70 which are placed on each side of the nacelle on each side ofits median plane in order to produce action on these ailerons in thesame manner as the sides of a deformable parallelogram. The two ailerons70 thus always remain parallel irrespective of their relativeorientation with respect to the median plane of the aircraft.

In the example described thus far, once the aircraft has lifted from theground, it is possible to modify simply its trim with respect to thehorizontal and thus to produce a forward or rearward thrust component bymodifying the position of the seat in accordance with an effort which isadjusted by the pilot himself. This in fact results in overallinclination of the rotary wings which produces the desired effect in aconventional manner.

In another alternative form of construction, arrangements can also bemade to obtain the thrust component to be exerted on the aircraft forthe purpose of producing its displacement, not by varying the trim ofthe entire unit by modifying the position of the pilot's seat, but byadapting on the nacelle 1 a suitable auxiliary wheel, the constructionof which is illustrated diagrammatically in FIG. 5.

Thus the side wall 3 of the nacelle is preferably provided substantiallyin the median plane of the aircraft with a shaped support 74 on whichthe hub 75 of a wheel 76 is capable of rotating freely. This wheel has ahollow rim 77 and a peripheral tire 78 applied in frictional contactwith the opposite surfaces of the two rings 40 and 41 or even preferablycooperating with these rings by means of a direct mechanical coupling,in which case the external tire 78 is provided with teeth 78a whichcooperate with grooves (without references) formed in opposite relationin the rings. The hollow rim 77 of the wheel has four (or more)orientable vanes or blades 79, control of orientation of which can becarried out in particular by means of a pinion 80 rigidly fixed to eachvane and in turn driven by a bevel-pinion 81 mounted at the end of anactuating shaft 82 or if necessary a pushrod.

Irrespective of the alternative form of construction employed forpropulsion of the aircraft, the aircraft in accordance with theinvention can also be provided, as illustrated in FIG. 3, with controlmeans and especially electrical control means which are fixed on therings 40 and 41 and make it possible to produce on demand apredetermined tractive force on the cables 66 and 67 by pivotallydisplacing the blades associated with the two drive rings, in particularwith a view to varying the inclination of said blades and the collectivepitch of the aircraft. To this end, each ring can be provided betweeneach pair of blades carried by this latter with a device showndiagrammatically at 83 in the drawings and constituted for example by atwo-position relay for controlling respectively two rods 84 and 85secured to the corresponding cables 66 and 67 in order to produce inthese latter a displacement force in one direction or in the other asindicated by the double arrow 86. Each ring 40 and 41 is provided with adevice 83 of this type, the design concept of which is such that itnevertheless permits, independently of the electrical control ofdisplacement of the cables in the manner thus specified, free motion ofthese latter for ensuring cyclic variation of pitch as is necessary forautomatic compensation for the effects of turbulences created duringoperation of the aircraft.

The pilot who is seated on his seat also has at his disposal a lateralhand-lever 87 for starting-up or stopping the engine 19, a hand-lever 88for engine throttle control and preferably in accordance with anothercharacteristic feature of the invention a system for producing betweenthe two drive rings 40 and 41 a torque of relative phase displacement ofone ring with respect to the other in order to ensure in this case alsoand in combination with the ailerons 70 an effect of banking or yaw ofthe aircraft.

To this end, there is mounted on each ring in the manner shown by way ofexample on the ring 40 a brake strip 89 fastened by means of a collar 90on the tube 2 of the nacelle placed opposite to the ring 40, said strip89 being applied against or on the contrary released from the edge ofthe ring against which it is applied in frictional contact by a cammechanism constituted in this case by a lever 92 pivotally mounted on apin 91 which is carried by the tube 2 and the nose-shaped free end 93 ofwhich is adapted according to the position of the lever to apply or onthe contrary to release the brake strip 89. A similar device is providedon the ring 41 in such a manner as to make it possible to modify at willthe relative torque of the wings carried by the two rings and to producea displacement of the aircraft either to the left or to the right as thecase may be.

The operation of the aircraft described in the foregoing can accordinglybe readily deduced from the indications already set forth. The nacelleis resting on the ground on which it is supported by its skids 6. Theengine 19 is started-up by the pilot who has previously taken his seatand strapped himself to the seat 9 by means of the operating lever 87.When the engine which is regulated by the hand-lever 88 has run-up to asuitable speed, the centrifugal clutch 29a establishes the necessarymechanical connection between the output shaft of the engine 24 and thetransmission shaft 36 which sets the driving wheel 37 in motion. Thiswheel then imparts rotational motion in opposite directions but at thesame speed on the one hand to the rings 40 and 41 which carry the blades48 and 49 and on the other hand to the blades 50 and 51 of the rotarywings. As a preliminary step, the pilot has adjusted the collectivepitch of these blades by means of the cables 66 and 67 by causing thesleeves 55 which carry these latter to undergo a pivotal displacementthrough a given angle in order to give a suitable orientation to theirinner and outer surfaces.

As the engine speed increases, so the speed of the blades increasesuntil the vertical resultant produced by virtue of their counterrotatingmotion makes it possible for the aircraft to rise into the air by virtueof a suitable incidence of the blades, the trim of the machine beingregulated by the pilot by displacing his seat in sliding motion so thatthe center of gravity of the entire structure is substantially placedalong the vertical axis.

Once the aircraft has reached the desired altitude, the pilot can theninitiate forward or backward displacement of the aircraft by varying thetrim so as to incline the blades as a result of a suitable displacementof his seat and of the center of gravity of the aircraft. By way ofalternative, if the aircraft is provided with an auxiliary drivingwheel, the pilot simply controls the orientation of the vanes 79 of saidwheel in order to produce the desired thrust component. During flight,the aircraft is naturally capable of undergoing lateral displacements inbanking or yawing motion by virtue of the ailerons or fins 70 and/or byproducing action on the brake strips 89, thus producing between the tworings 40 and 41 a relative phase-displacement torque which introduces asuitable lateral-displacement component.

During the movements of the aircraft, the pitch of the blades iscontinuously adjusted by virtue of the opposing action of the cables 66and 67 which connect the two blades of one and the same pair each timewith automatic pitch correction as required by the effects ofturbulences or other effects which produce action on these blades.Moreover, in the event of failure of the engine 19, a detector (notshown) permits automatic disengagement of the centrifugal clutch 27awhilst the fly-wheel 34 serves to produce autorotation of the wingblades by means of the free-wheel 35, thus permitting immediateprogressive descent of the aircraft to the ground.

There is thus provided a rotary-wing aircraft of very simple designhaving the following characteristics which are given solely by way ofindication and which can be contemplated in a particular example ofconstruction.

    ______________________________________                                        OVERALL DIMENSIONS:                                                           Rotor support rings:                                                          Internal diameter        100     mm                                           External diameter        120     mm                                           Fuel tanks:                                                                   Unitary capacity                                                              Blades:                                                                       Length                   200     mm                                           Width                    21      mm                                           WEIGHT:                                                                       Engine                   28      kg                                           Rotor support rings (× 2)                                                                        16      kg                                           Nacelle                  28      kg                                           Wheels with transmission 8       kg                                           Blades (× 4)       20      kg                                           Fuel (approx.)           20      kg                                           User (lower than or equal to)                                                                          90      kg                                           Maximum total weight in working conditions                                                             210     kg                                           ______________________________________                                    

A minimum thrust of 300 daN is thus sufficient for vertical takeoff ofthe aircraft, hence the choice of an engine power rating approximately40 KWA.

The aircraft in accordance with the invention can have a large number ofapplications, especially for uses in sporting events, observation orsurveillance missions and in a general manner each time it is desired toemploy a "ULM" (Ultra-Light Motorized) machine which permits movementsof a pilot in a simple machine which is light and inexpensive.

It is readily apparent that, as already stated, the invention is notlimited to the examples which have been more especially described andillustrated but also includes all alternative forms. In particular, itwould be perfectly possible to contemplate construction of the aircraftin such a manner as to ensure transportation of several persons insteadof only one. In this case, the construction of the nacelle could besubjected to alternative forms of arrangement without thereby departingfrom the scope of the present invention.

I claim:
 1. Rotary-wing aircraft, characterized in that it comprises anacelle (1) surrounding the user who is seated on a seat (9) mounted inthe median plane of said nacelle for sliding motion substantially in thenormal direction of displacement of the aircraft in flight, two parallelrings (40-41) carried by the nacelle and driven in identical movementsof rotation but in opposite directions about a common axis extendingsubstantially at the center of the nacelle at right angles to the planeof said rings, the function of each ring being to support at least onepair of wing-blades (48-49, 50-51) or airfoils which are diametricallyopposite and located in the line of extension of each other, means(19-37) for driving the rings about the nacelle and means (66-67)whereby the blade pitch in each pair of blades can be varied in an equalbut opposite manner in each case, each ring (40-41) being providedopposite to each blade (48 to 50) with an axial stud (54) which supportsthis latter, which is fitted with a needle thrust-bearing (58) and onwhich is engaged a sleeve (55) so designed as to be capable of pivotingabout the stud, said sleeve being provided with an extension in the formof a stirrup-piece (61), the end of the blade being mounted and fixedbetween the two arms of said stirrup-piece so as to permit a variationin pitch of the blade with respect to the ring by relative rotation ofthe sleeve, each blade of the airfoil having two transverse extensions(63-64) located in alignment with each other, the blades of one and thesame pair (48-49, 50-51) being joined together around the nacelle bymeans of two crossed and tensioned cables (66, 67) fixed at the end ofsaid extensions respectively at the opposite extremities thereof so thata tractive force exerted in one direction on one of the cables resultsin an opposite tractive force on the other cable and conversely, the twoblades of the same pair being thus capable of pivoting about their axialsupporting studs with an equal and opposite amplitude of rotation. 2.Aircraft in accordance with claim 1, characterized in that the tensionapplied to the cables (66-67) for ensuring relative pivotal displacementof the blades is adjusted by means of an assembly of distance-bars orsimilar tensioning devices associated with the support extensions(63-64).
 3. Aircraft according to claim 1, the position of the twocrossed cables (66-67) for determining the pitch of the blades beingcontrolled by means of electromagnetic devices (83) having two positionsor by means of a stepping motor or of a reduction-gear motor forensuring relative displacement of these cables in opposite directions.4. Rotary-wing aircraft, characterized in that it comprises a nacelle(1) surrounding the user who is seated on a seat (9) mounted in themedian plane of said nacelle for sliding motion substantially in thenormal direction of displacement of the aircraft in flight, two parallelrings (40-41) carried by the nacelle and driven in identical movementsof rotation but in opposite directions about a common axis extendingsubstantially at the center of the nacelle at right angles to the planeof said rings, the function of each ring being to support at least onepair of wing-blades (48-49, 50-51) or airfoils which are diametricallyopposite and located in the line of extension of each other, means19-37) for driving the rings about the nacelle and means (66-67) wherebythe blade pitch in each pair of blades can be varied in an equal butopposite manner in each case, the nacelle (1) carrying at the endopposite to the ring-displacement driving wheel (34) an auxiliary wheel(76) which is freely driven by the movement of said rings (40-31), theaxis of the auxiliary wheel being located in the median plane of thenacelle opposite to that of the driving wheel (37), the auxiliary wheel(76) being provided with a set of orientable radial vanes (79) adaptedto generate a forward aircraft-flight component in the direction of saidmedian plane.